Wind power refers to the conversion of wind energy into a useful form of energy, such as electricity. Wind energy is an attractive power source that is an alternative to fossil fuels because it is plentiful, renewable, widely distributed, clean, and produces no greenhouse gas emissions. Wind energy currently accounts for about 1.5% of worldwide electricity usage, and approximately eighty countries around the world use wind power on a commercial basis (World Wind Energy Report 2008: Report, World Wind Energy Association, February 2009; and Worldwatch Institute: Wind Power Increase in 2008 Exceeds 10-year Average Growth Rate, May 2009). Further, world wind generation capacity has more than quadrupled between the years 2000 and 2006, doubling about every three years.
Offshore wind turbines harness the energy of powerful winds native to deep sea waters to generate electricity. Access to these turbines is critical for their continued maintenance, however, the harsh waters of the deep sea make reaching the turbine by ship exceedingly difficult. A ship might not be able to reach a wind turbine for several weeks due to inclement weather conditions. The resulting downtimes due to lack of repair can cut significantly into energy production.
Alternate means of reaching the turbine include travel by helicopter, which has its own challenges. Helicopter decks associated with three-bladed wind turbines present substantial risks due to the constant presence of at least one of the three turbine blades extending vertically at any given time. A helicopter can potentially collide with these vertically-oriented blades during operations. Attempts to mitigate this danger include mounting the helicopter deck to the rear of the nacelle, away from the blades. A mounted helideck, however, can increase manufacturing cost, increase the weight of the nacelle, and when the deck is positioned to the rear of the nacelle, the action of the wind could produce dynamic excitation. Moreover, the danger due to the vertically-positioned blade is still present. Accordingly, there is a need for a helicopter deck and associated nacelle with improved safety, better stability, and lower production costs.